Spark plug question?

[NgtvNrg]

I have a 1996 Evinrude 90 an was changing the spark plugs. It currently has Champion ql82c. I bought champion ql77jc4. According to this chart http://www.boatsetup.com/SparkPlugChart.pdf I can use either one. Which one is preferred and what are the differences?

 

[Dhadley]

Re: Spark plug question?

In that motor I'd prefer the 77's myself. They're a tad bit cooler. Either will work just fine.

 

[Rev.]

Re: Spark plug question?

i believe, one plug is just hotter than the other. alot depends on the climate where you live, if you live in a cooler climate, you might want to run alittle hotter plug, hotter climate, cooler plug.

 

[NgtvNrg]

Re: Spark plug question?

Thanks, I will use the ql77jc4's because it's hot here. I saw somewhere on here to gap them at .40 so it idles smoother, is that right?

 

[Dhadley]

Re: Spark plug question?

Probably won't idle at .40 and not sure you can get it that far. But .040 is great. (Sorry, couldn't resist)

 

[Rev.]

Re: Spark plug question?

think i'd probably try 30 - 35 first.

 

[cougar1985]

Re: Spark plug question?

i find that .040 is a good gap for trolling with my 90 (1982).